Sustainable urban renewal is seen today as one of the keys towards unlocking the quest for a sustainable society. As a central paradigm of sustainable urban renewal, the low-carbon renewal is promoted by global and local policies as one of the preferred responses to the challenges of sustainable development. From the existing studies, urban renewal cases pay more attention to the level of strategies and technologies, and there is a lack of research on the systematic operation mode of low-carbon goals and corresponding examples. Stockholm Royal Seaport, which began construction in 2009, is Sweden’s most ambitious, large-scale, and carbon–neutral sustainable urban renewal project in recent years. To illuminate the operation mode of the low-carbon renewal district accordingly, a descriptive case study is adopted as a qualitative research methodology, where the empirical basis is mainly formed by urban planning and development documents of Stockholm Royal Seaport—in combination with qualitative interview data, secondary data, and scientific literature. This study shows four types of key operational systems and their interrelationships, which are carbon reduction target, five goals for Sustainable development, urban renewal strategic planning and assessment of results for sustainable development. The study reveals the coupling of its renewal process based on carbon reduction and sink enhancement requirements. It is of great significance for the refined development of low-carbon urban renewal in the international scope and the scientific implementation of renewal planning.